Method and apparatus for processing coded aperture radar (CAR) signals

Abstract

A radar system in which Coded Aperture Radar processing is performed on received radar signals reflected by one or more objects in a field of view which reflect a transmitted signal which covers a field of view with K sweeps and each sweep including Q frequency changes. For Type II CAR, the transmitted signal also includes N modulated codes per frequency step. The received radar signals are modulated by a plurality of binary modulators the results of which are applied to a mixer. The output of the mixer, for one acquisition results in a set of Q·K (for Type I CAR) or Q·K·N (for Type II CAR) complex data samples, is distributed among a number of digital channels, each corresponding to a desired beam direction. For each channel, the complex digital samples are multiplied, sample by sample, by a complex signal mask that is different for each channel.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61 / 912,990, filed Dec. 6, 2013 and entitled “A Method and Apparatus for Processing Coded Aperture Radar Signals”. The disclosure of that U.S. Provisional Patent Application Ser. No. 61 / 912,990, is hereby incorporated herein by this reference.[0002]This application is related to U.S. patent application Ser. No. 13 / 490,607 filed Jun. 7, 2012 and entitled “Coded Aperture Beam Analysis Method and Apparatus”, the disclosure of which is hereby incorporated herein by reference.[0003]This application is also related to U.S. patent application Ser. No. 13 / 725,621, filed Dec. 21, 2012 and entitled “Coded Aperture Beam Analysis Method and Apparatus”, the disclosure of which is hereby incorporated herein by reference.[0004]This application is also related to U.S. patent application Ser. No. ______ filed on the same date as this application, Dec. 4, 201...

AI Technical Summary

Benefits of technology

[0012]In one aspect the present invention provides a method of processing radar signals reflected from one or more objects in a field of view of a radar transmitter transmitting the radar signals. The method includes receiving and modulating the radar signals reflected from the one or more objects by plurality of binary phase shifters to produce a set of modulated signals, the binary phase shifters being controlled by binary coding data; summing the modulated signals and down converting them, preferably to base band, by a mixer producing in-phase and quadrature output signals which are each sampled and digitized by one or more A/D convertors to produce a set of real and imaginary digital values corresponding to the in-phase and quadrature output signals produced by the mixer during an acquisition of the field of view; distributing real and imaginary digital values corresponding to the in-phase and quadrature output signals produced by the mixer into a number of channels, the number of channels being equal to a number of desired radar beam directions to be processed concurrently and each channel having real and imaginary digital values corresponding to the digitized in-phase and quadrature signals output by the mixer; performing a complex multiplication using the real and imaginary digital values in each channel...

Problems solved by technology

CAR is a new technology that has not yet been implemented in IC form, therefore is no known prior art for processing methods and hardware for CAR signals.

This technique is effective, but requires an often prohibitive amount of memory to store the reference signals, and significant computation to perform the correlations in a CPU (for example).

This is highly computationally intensive and in...

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